arctan7 + 2.arccot1/3=?
üs ve kök yazma düzeltildi
Dik üçgenlerden:
Arctan7=A ise sinA=7/√50 ve cosA=1/√50
Arccot=1/3 ise sinB=3/√10 ve cosB=1/√10
sin(A+2B)=sinA.cos2B+sin2B.cosA
=sinA[2(cosB)²-1]+2sinB.cosB.cosA
=[7/√50][2(1/10)-1]+2(3/10)(1/√50)
=-56/[10√50]+6/[10√50]
=-50/[10√50]
=-√50/10
=-√2/2 ise A+2B=225 veya 315